Pressure-responsive device for thermostats.



Patented Feb. 13, 1917;.

N. HOFSTAD.

[fa-W527 I flfaf/ Lad APPLICATION FILED APR. I0, I9I6.

PRESSURE RESPONSIVE DEVICE FOR THERMOSTATS.

wa n MEDIH CO L V COLD mmawo NELS HOFSTAID, OF CHICAGO, ILLINOIS.

Devices for Thermostats, of which the fol-' lowing is a specification.

My invention relates to pressure responsive device for thermostats and has especlal controlling. valves, or the like. One of the salient objects of my invention is to improve the structure of such devices and more particularlyto providemore du- I rable, eflicient. and reliable-pressure respons1ve means for moving the valve opera-ting Parts. I

Another object of myinvention is m; ro-

vide av protecting device for the sensitive pressure-responsive'means, to protect it 1 against injury bypnncture, from medling persons and whereby itsfmojvementis more positively transmitted to apart to be moved thereby.

Other and further objects of my inventionwill become" readilyapparent, to persons skilled in the art, from a consideration of the following description when takenin conjunction with thehdravvings, wherein:-

Figure 1 is a planiview'of adevice embodying my improvement.

Fig; 2 is a section thereof taken on line 2--2 of Fig. 1.

Fig. 3 is a transverse 3-3 'of Fig. 2.

In all the views the same reference characters are employed to indicate similar parts. My invention is especially applicable to section taken on line and useful inconnection with a somewhat similar device fully set forth and disclosed in United States Letters Patent No. 1,109,993 granted September 8th, 1914.

In describing my improvements of such instruments; therefore, I shall refer only to such parts of the entire structure as are necessary to a complete. description and disclosure of its operation: It'is to be understood, however,zthat my invention is not .to

be limited in its use to the specific structure with which itis shown to be associated as it may be used in many other environments,

being limited only by the scope of the appended claim.

In the operation of the thermostatic desra ris races Specification of Letters Patent.

carrying a central perforation 16.

material which consists of a disk 21 FGE.

Patented Feb. is, rat a.

Application filed April 10, 1916. Serial No. 90,974.

vice it becomes necessary to move the valve moving motor-arm 5 upon its pivot 6 to move the three way air valve-7 in response to temperature conditions which act on the thermostatic bar 8 to produce the desired movement. The frame 9, carryingthe apparatus, is mounted upon a plaster back 10 i which is secured to the wall. or other sup? port, by nails or screws, that pass through the perforations 11. reference to devices of. this character for The specific invention sought to be pro tected' in this application consists of the air responsivedevice 12 which is a metallic bellows diaphragm structure consisting of a plurality of dlaphragms specifically the diaphragms 13 and 14, suitably secured together at their peripheral edges, the latter being centrally perforated for a nippleTllf,

e frame 9 is provided with'ian aperture 17, which is screw threaded for the nipple 15 but is somewhat deeper than necessary for the accommodation of .thenipple and which is flanked by a communicating duct, or opening 18, which in turn communicates with a chamber surrounding theneedle valve 19, through the port of which, a r is admitted through the-1duct'18 land from thence into the chamber between the diaphragms 13 and 1 1, to expand thesame. The 'diaphragms 13 and-14 are annularlycorrugated and are necessarily made of relatively thin, flexible metal, sensitive to rough usage and liable to rupture when violently contacted by sharp pointed instruments, or the like. To protect the diaphragms from such resultant damage from such or other causes I provide a cap, or covering 20, of relatively thick heavy rovided with a side flange 22 to hold it u pon the diaphragm structure. This cap or cover 20 is sufiiciently stifl' to transmit the power produced by the expanding diaphragm structure 12 to the motor arm 5, that is normally in contact therewith. To further protect the diaphragm 13 I provide a relatively yielding soft cushion 23, such as a disk of fabic, such asfmuslin, contained between'the inner surface of the cap 20 and the said diaphragms. This prevents unnecessary wear upon the diaphragm and acts as a cushion to protect it from injury from sudden impact producing movement.

' The metallic diaphragm structure, which is the subject of my invention, may be easily i and ,quickly replaced in the frame of the thermostatic .valve device; is not subject to leakby deterioration, as is the case with a rubber diaphragm as by the action of the oil that may come through with the compressed air that is admitted to the expansion chamber; is so constructed and arranged that all of the expansive effect produced by the air admitted thereto is communicable to the part to be moved thereby and, therefore, it is economical in the use of air for producing a given result. It reduces the number of separable parts necessary for the structure, of the device as a whole, and is inclosed in a protecting shield or cap which does not modify the sensitiveness of the expanding portions of the diaphragm and transmits the entire motion of the diaphragms to the part to be moved thereby. The cap 20 also limits the effective movement of the diaphragm structure in one direction, as shown inthe drawings.

Having described my invention, what I claim is v A diaphragm structure comprising a plurality of expansible diaphragms connected together at their peripheries; a connection to a terminal diaphragm; a protecting cap substantially inclosing said diaphragms and movable with the other terminal diaphragm of the series to transmit-motion produced thereby, and a cushion disk of relatively soft material within said cap.

In testimony whereof I hereunto set my hand in the presence of two subscribing witnesses.

NELS HOFSTAD. In the presence of-- Fonr'm BAIN, MARY F. ALLEN. 

